Molecular Dynamics Study On The Interaction Of Carbon Nanotubes And Phospholipid Bilayers

The preparation and use of nanomaterials is one of the important branches of nanotechnology,of which carbon nanomaterials are being developed into the current research focus.As a representative carbon nanomaterial,carbon nanotubes have broad application prospects in the fields of drug carriers,gene carriers,bioimaging,antiviral,antibacterial,and biosensors.Although the reactions induced by carbon nanotubes in vivo may be complex and diverse,these reactions,without exception,require that the carbon nanotubes first cross the biofilm barrier before they can eventually reach the target cell compartment.Therefore,it is very important to elucidate the interface mechanism between carbon nanotubes and biofilms.In this paper,the interaction between carbon nanotubes and biofilms was simulated by molecular dynamics.According to the characteristics of the simulation,the namd platform was selected as the main molecular dynamics research method.The main composition and structure of biofilms are phospholipid bilayers,and phospholipid molecules play a major role in the interaction between biofilms and carbon nanotubes.Therefore,biofilms are simplified as phospholipid bilayers..This article focuses on the use of more single-wall carbon nanotubes?SWCNT?as the main object.First,a pure single-walled carbon nanotube model and a phospholipid bilayer model were established,and the interaction between SWCNT and the phospholipid bilayer was simulated under natural conditions.The effects of different spatial positions of SWCNTs,different solution environments,and different SWCNT size on the interaction between the two were investigated.It was found that these three factors did not have a significant effect on the simulation process.Therefore,the complex model and the deep simulation were continued on this basis.To investigate the behavior of SWCNTs exhibiting different angulation angles during interaction with phospholipid bilayers under different sized external forces,and the conformational changes of the phospholipid bilayer during this process.At the same time,after understanding the basic situation of the SWCNT interaction with the phospholipid bilayer,functionalization of the SWCNTs was performed,namely modifying the charged group at the SWCNT end to give it four carboxyl groups?COO-?.The interaction between carboxyl-modified single-walled carbon nanotubes and phospholipid bilayers was simulated,and the effect of different solution environments of Na Cl and CaCl₂ on the process was explored.It was found that when the SWCNTs were modified with negatively charged groups,they appeared to have a repulsive effect with the phospholipid bilayer,but in the ionic solution environment,the repulsion was moderated.The negatively charged group of SWCNT-COO-and the hydrophilic layer of the phospholipid bilayer both have attractive effects on the cations,but both have a different degree of attraction to cations,making the cations in SWCNT-COO-and phospholipid bilayers.The interface cannot form a bridge,making SWCNT-COO-stable on the surface of the phospholipid bilayer.